ABSTRACT Alcohol use disorders (AUDs) are a major public health problem and pose significant challenges to clinicians, patients, and health systems. AUDs are associated with serious medical conditions, can complicate medical treatment and increase avoidable health service utilization and costs. Yet most patients who would benefit from evidence-based AUD treatment, including pharmacotherapy, do not receive these services. Although medications such as naltrexone, acamprosate and disulfiram can be effective for moderate to severe alcohol problems, primary care providers (PCPs) are often reluctant to prescribe, and AUD medications remain underused. Innovative care models are needed to give PCPs the tools they need to address AUDs in primary care settings, but few studies have examined interventions to improve AUD medication delivery and specialty care initiation. To address this substantial gap in the evidence base, this pragmatic, cluster-randomized trial in adult primary care clinics (n=20) in a large, ethnically and socioeconomically diverse healthcare system, will examine the effectiveness of an innovative, multi-faceted intervention: the Addiction Telemedicine Consultant service, or ?ATC.? The ATC provides a flexible, efficient, centralized approach to bringing Addiction Medicine expertise directly into primary care. PCPs can access the ATC via three routes: real-time video or telephone connection during primary care visits, asynchronous email, and telephone consultation. The ATC, a clinical pharmacist, may assess the patient, discuss appropriate AUD medications with the PCP and patient, and if appropriate, guide the PCP through prescribing logistics, or initiate the prescription themselves. The motivational interviewing-trained ATC may also encourage the patient to initiate specialty addiction treatment and facilitate connection to a local program. The ATC intervention will also offer initial continuing medical education training on AUDs and AUD medication prescribing, and ongoing technical assistance, to all PCPs in the ATC arm. We will compare the ATC arm to Usual Care, which includes routine alcohol screening, brief intervention and referral to treatment (SBIRT) in primary care. We conducted a pilot feasibility study of the ATC model, and the proposed trial builds on our pilot findings, the extant literature, and incorporates stakeholder feedback in its design. We will use electronic health record data captured during the course of regular clinical care to examine treatment arm effects on implementation outcomes (AUD medication prescription rates and addiction treatment referral rates) and patient outcomes (AUD medication fill rates, addiction treatment initiation, alcohol use (drinking days/week, # drinks/week, # of ?heavy? drinking days (4+/5+/day) in past 90 days), and health services utilization and costs, over two years. If the intervention is effective, this study has the capacity to spur the use of safe, effective pharmacotherapy for AUDs as a standard practice in primary care settings and profoundly affect how we treat and study the full spectrum of alcohol use problems.